Compressor-controlling mechanism



Nov. 22, 1927.

c. B. OFFICER COMPRESSOR CONTROLLING mzcmmxsm Filed Aug. 10, 1923 Patented Nov. 22, 1927.

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CHARLES 1B. OFFICER, OF CHICAGO, ILLINOIS,-.ASSIGNO R SULLIVAN MAQHI NERY? COMPANY, A CORPORATION: OF MASSACHUSETTS; Y

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Application filedAugus t 10, 1923; Serial No. 656,736.

My invention relates: to compressor controllingmechanism, and more particularly to controlling mechanism for electrically driven compressors.

An object of'my invention is to provide to current cost it is desirable to maint ain the peak" demand as little above the inaxlmum runningdemand as is possible. It is there-- fore undesirable, when the compressor is" running unloaded, for it to take its loadat a time when other motors forming the remaining portion of the equipment of, the plant are-beingstartedup, for-by maintaining the compressor momentarily unloaded until the other motor or motors-haveassumed their normal running characteristics-,. it. will be possible to' reduce the peak demand for} the current materially; It is a" more specificobj'ectof my inventionto' provide; an. imj-. proved controlling, mechanismfor com pressorwhich will prevent-the loading of the compressor at; such time as othenmotor 3 driven equipment o-f a shop is drawing so heavily on the supplylinesthat an excessive current demand would be created by: the throwing of-the load upon the: compressor driving motor; Otherobjects and advantages of my inventionwill hereinafter more fullyapear;

In. the accompanying drawings I have shown for-purposes of illustration one form which my invention, may assume in practice.

In these drawings;-

Fig: 1" i'sa view partially-in side elevation and partiallydiagrammatic; showing a compressor' system constructed in accordance motors shown, theseybeingdesignated respec- I tively 1 and 25although it'will be understood that th'ere'may'he a plurality of'motorsbesides thecompressor drivingmotor. Each with one illustrative embodiment of m in;

of thesemotors provided with a control-- '1ing .sWitch,"herein only diagrammatically illustrated but respectively designated} 3 and 4; Motor 1' maybe used for anypunposewh-il'e-motor 2 is the driving motor for a, compressor 5 which is herein shown as of? the angle-compound type comprising a low, pressurecylinder 6 discharging through an intercooler 7 which initsturn. opens into the: high pressure cylinder 8 arranged at right angles to'the low. pressure cylinder 6,; The

high pressure cylinder 8 in its turn discharges through'a pipe line 9 to areceiverl o; Suitable intake closure unloading mechanism generally designated 11 isarranged to coloperate with the low pressure cylinder 6 and for the purpose ofcontrollingrthismechanism a, pipe line 12 leads fromihe, receiver lO'and' communicates with 21 pilot, valve 13;. VV-henthe receiver pressure. is in excess offa,

predetermined" amount the pilot valve 131.

will permit the passage of. fluid, from the pipe 12 to the, unloading mechanism 11 and will cause closure of. the intake unloading valve and so unloading oi the compressorj When on the other hand the receiver pres,- sure falls to; a certainQfiXed: limit,, the pilot, valve 13' will close and? Will -vent unloading mechanism 11, and cause.v reloading of; the compressor to take 1913-06. T e twolnotors. 1 nd2i taketheir curre t from l'inecondum tors. 15;;16 controlled. by. 31 main. line. switchl?) As one. possible examp e of. a; p ant n. which invention willbe de irable... let. it beassumed that the combined. full; load, current demand of both motors .i's.1ess.tha n. the current; that will be. taken with thecom v pressor running unl adedland,wi hiheo h r motor starting so; that, the: last mentioned condition. may, dietermihei he pe dem d, It oulId. evidently be. undesirable. to mload. the compressor at. a moment-when the m or. was st rting. as. thiswould, carry up;v thesc'urrrent. demand above. the maximum at d;

- Accordingly}; means; is. provided. in: con rol; ling thezloajding. of, thenompressor controlled;

y the. Cu n ak n. from l ne condu tors. 1-5; 16 operative to preventloading' whenthe} current dr wn. is equal. to the demandiwhen motor. 1- is. starting-and; motor running withgthe. compressor; unloaded. Ihi's'jjs .a g compfishedj by,- arranging beyond'jfthe, in. l ne'switch. '17. in, thefline conductor, 15;? which leads to one side of'the motors'a 'rel- 110,

atively heavy coil of a few turns in series in the line. A plunger 19 is arranged within this coil and depending upon the current taken by the motors the field of this magnet will be increased or diminished. The switch 20 is arranged in a manner to be controlled by the plunger 19. hereinbeing connected thereto by a link 21'which may preferably be constructed of insulating material so as to prevent any undesired current flow or chance of injury. .The spring 22 prevents the closure of the switch 20 except in case the current flowing through the coil 18 rises valve 13. It will be noted that the pistonvalve 27 is normally maintained in a position to interrupt communication between the mechanism 11 and the line 12 but that when the solenoid 25 is energized the piston valve will be moved to open communication through the line 29. Itwill of course be understood that pressure admitted through the line 29 and shunt into the unloading mechanism by closure of valve 27 will be vented by the pilot valve 13,. but that the rate of supply through the passage 29 is greater than can be taken care of by the 7 vent in the pilot valve 13.

The mode of operation of this mechanism will be clearly apparent. Assume that the motor 2 is running, and that the compressor is loaded. When motorl isthrown upon the line, the current passing through the coil 18 will be so great as to instantly cause closure of the switch 20 and the energization .of the coil 25 will cause the plunger 26 to move the valve 27 to admit pressure to unload the compressor by its action in the un- This action will 1 loading mechanism 11. obviouslybe very rapid and will reduce the current consumption so quicklyas to avoid an increased rate. Consider again that the compressor is unloaded and that it is intended to start the motor 1 and that just as the motor 1 is starting the pilot valve 13 should operate to vent the unloading mechanism. This would permit the compressor to load but for the operation of the solenoid 18. which being again energized sufliciently to close the switch 20 would cause the passage of fluid through the by-pass 29 and prevent reloading until after the current demand of the motor 1 had dropped.

' While I have in this application specifically described oneform which my invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is: v i

1. In combination, a compressor, a plurality of motors including a motor for driv ing said compressor, a source of electric current for driving said motors, and unloading means for said compressor including a plurality of operating medium supplies one oi which is controlled by the current drawn by the motors from said source and another of which is independent of said. electric current, said current controlled supply being adapted to deliver operating medium for unloading the compressor. if the independent supply should induce loading of the compressor when the current con sumption from said source exceeds a predetermined amount.

2. In combination, a compressor, a re ceiver, a plurality of motors including a motor for driving said compressor, a source. of electric current for driving said motors, and unloading means for said compressor including a plurality of operating medium supplies one of which is controlledby fluid pressure in said receiver and; a second of which is controlled by the current drawn from said source by said motors.

rent, a plurality of motors adapted to be supplied from said source, a compressor driven by one of said motors, unloading means adapted to unload said compressor upon actuating medium being supplied to said means, compressor discharge pressure governed controllingmeans for the supply of such medium, and means for taking the control of the supply away from said last mentioned means governed byapredetermined amount of current drawn from said source by said plurality of motors.

4. In combination, a source of electric current, a, plurality of motors adapted to be supplied from said source, a compressor drivenflbv one of said motors, unloading means for said compressor, compressor dis-- charge pressure governed controlling means for said unloading means, and means for taking the control of said unloading means away from said last mentioned means governed by-the current drawn from said source by said plurality of motors including means for bypassing the compressor. discharge pressure governed means, said current cone trolled means being'operative only upon a predetermined amount of current flow.

5. In combination, a source of electric current, a pluralityof motors adapted to be supplied from said source simultaneously while carrying a normal full load, a com pressor driven by one of said motors, unloading means for said compressor, compres- 3. In combination, a source of electric curlOO ins"

sor discharge pressure governed controlling means for said unloading means, and means for taking the control of said unloading means away from said last mentioned means governed by the current drawn from said source by said plurality of motors including solenoid controlled bypass means for shunting said compressor discharge pressure governed means.

6. In combination, a source of electric current, a plurality of motors supplied therefrom, a compressor driven by one of said motors, a solenoid through which all the current passing to said motors flows, and means controlled by said solenoid for unloading the compressor when current in excess of a predetermined amount flows through said solenoid.

7. In combination, a source of electric current, a plurality of motors supplied therefrom, a compressor driven by one of said motors, a solenod through which all the current passing to said motors flows, and

means controlled by said solenoid for un loading the compressor when current in excess of a predetermlned amount flows through said solenoid, said last mentioned means including an electrically controlled valve mechanism and a controlling switch for the lattercontrolled by said solenoid.

8. In combination, a source of electric current, a plurality of motors supplied therefrom, a compressor driven by one of said motors, a fluid pressure operated unloading mechanism for said compressor, a pilot valve for supplying fluid pressure thereto and venting fluid therefrom, a connection from a source of pressure leading to said pilot valve, a bypass around said pilot valve, and means in said bypass automatically controlled'to effect unloading of said compressor only when the amount of current flow from said source to said plurality of motors reaches a predetermined amount.

9. In combination, a compressor having a fluid operated unloading mechanism, and means for rendering the same operative including a circuit in which current flows throughout running of the compressor and in which current below a predetermined value will flow without affecting said unloading mechanism, means independent of said compressor for varying the current flow 7 1n sald circuit, and means whereby when said current flow reaches a predetermined amount fluid is admitted to said unloading mechanism to render the same operative.

10. In combination, a compressor, a lurality of motors including a motor for riving said compressor, a'source of electric current for driving said motors, unloading means adapted to unload said compressor upon actuating medium being supplied'to said means, compressor discharge pressure governed controllingmeans for the supply of such medium, and means governed by a predetermined amount of current drawn from said source by said plurality of motors controlling the supply of such medium. Intestimony whereof I aflix my signature.

CHARLES B. OFFICER. 

